Straightening press for aircraft propellers and the like



Jan. 22,. 1946. I w. C(EDWARDS. JR., ET AL 2,393,317

STRAIGHTENING PRESS.FQR AIRCRAFT PROPELLERS AND THE LIKE Filed Feb. 9,1944 3 Sheets-Sheet 1 Jan. 22 9 6- w. c. EDWARDS. JR., ET AL 3,

STRAIGHTENING PRESS FOR AIRCRAFT PROPELLERS AND THE LIKE Filed Feb. 9,1944 3 Sheets-Sheet 2 F'naz INVENTOR 14 14 1. 04M 6. Eon 4120s, P.

Fa s-P72 51.4

n- 22, 1946- w. c. EDWARDS. JR., ETAL ,3

STRAIGHTENING PRESS FOR AIRCRAFT PROP KILLERS- AND THE LIKE Filed F815.9, 1944 3 Sheets-Sheet :5

)NVENTOR CJMIOJIJR. 5527-1 52.4

LIL/4M able pitch propeller Patented Jan. 22, 1946 PRESS FOR-AIRCRAFT vI.STItAIGHTENING PRQPELLERS AND TliEiLlKE Q Jr andR obertP.1Elam.' '1 'Dawt0,n,Ohio";I v a 9,1944,SerialNo; 521,610: r ,1.Cla.im., (01. 153-32):

": William 0. Edwards,

ApplicationFebruai-y The invention described herein may be manu or forthe Government for the payment to factured and used by governmentalpurposes, without us of any royalty thereon.

This invention relates to andis particularly useful in straighteningpropellers, landing gear forks and similar aircraft parts.

According to well established rules in propeller blade design, everypart of the surface of a variblade must be in an exact position withrespect to the axis of the shank upon which the blade turns whenchanging the pitch. For this reason it is practically impossible tostraighten a bent or twisted propeller blade in any of the straighteningpresses which are commercially available at this time.

It is therefore an objectof this invention to provide a press in whichthe shank of the propeller blade or similar part is held in the presswith its axis parallel to the plane of a, gauging surface from whichselected parts of the surface of the blade may be checked to determinewhether a selected point on the surface is in proper relation with theshank axis, together with means to bend or twist any part of a blade tobring the gauged points in their proper position.

Another object is to provide a press in which a matched pair of bladesmay be straightened at the same time to the end that less frequentresettings of the gauge means will be required.

Other objects and advantages will be seen as the invention is furtherdescribed and reference is made to the drawings wherein:

Fig. 1 is a perspective, view of a press which straightening presses,

(cases under theact of March amended April 30,1928; 370 0.

externally threaded collar 44 embodies the principles of the invention,ar--;

ranged for straightening a pair of propeller blades simultaneously.

Fig. 2 is a cross-sectional view of one form of fixture used on thepress for supporting the shank of a propeller blade.

Fig. 3 is a cross-sectional view of anotherform of fixture used on thepress for supporting the shank of a propeller blade.

Fig. 4 is a perspective view of an arrangement for moving certain partsof the press to selected positions. I

Fig. 5 is a perspective view showing the construction of the gaugingmeans.

Like reference characters refer to like parts throughout the severalviews.

Referring now to the drawings, a press III, which is to serve as. anillustrative embodiment of subject invention, consists essentially of atable l2, which may be provided with legs l4 braced as to clamp theblade in proper Mounted 3,1883, as 1 G. 7151) at It and I8, endhousings20 and 22, which may be integral or permanently secured to the ends ofthe table, and a securely fastened on, the top ,endsofthehousingsysthewholebeing strengthened by struts 26, as shown. l

. Secured to; the inside face of the end housings are adapters 28 and30, which may preferably be in axial alignment one with the other,theaxis of theadapters being parallel to the plane of the table top.Adapters 28 and 30, shownto a larger scale in Fig. 3, are designed to'receive the shanks of a blade and clamp it sothat the axisupon which theblade turns in changing the pitch is parallel .tothe plane of thetabletop. I The adapt.- ers shown enlarged in Fig. 3 and inthe "press inFig. l, have bases 32 which are held byb01tS-34 to the end housings,pilots 36 which lit the bore of the blade shank, and two-part clampingrings 38 which are drawn up by bolts 40' and thus engage shoulders onthe blade shanks to secure the blades both againstaxial movement andagainst unwanted rotation. I

' An adapter 42, shown in-Fig. 2, is provided for aligning'blades by theoutside of'their shanks,

being provided with an and the adapter with a true bore 46 for thebearings 48, and an internal thread 50 into which the collar is screwedalignment. The adapter 42 has a base of the same dimensions as theadapter 3|], is drilled for the bolts 34 and will interchange with theadapter 30 when required.

this type of blade usually for straightening in the press I0 is a pairof blades 52 and 54, the blade 52 having been bent flatwise and theblade 54 having been twisted. For straightening the blade 52, the screwjacks 56 and 58 are set adjacent the bend and tightened after which thehydraulic jack 60 is used for bending the free end of the blade backinto alignment.

For removing the twist from the blade 54 a pair of clamps 62 and 6415provided. Each clamp is in two parts hollowed out as at 66 to fit theblade contour and drawn together on the blade by screws 68. The clamps62 and 64 are placed adjacent the portion of the blade which has thetwist in it, the twisted portion being between the Where the nature ofthe work is such that a platen 24 integral with, or V the blade aregiven with to :the blade :axis.

considerable number of screw jacks are needed on the upper side of ablade and it is required that they be moved to many different positionson the platen in straightening a single blade, an arrangement such as isshown in Fig. 4 is provided for-movablyv suspending the jacksfrom theplaten. Here a -series :of hangers 18 are :slidable endwise on theplaten 24, the hangers having T- slots 82 which extend through thehangers crosswise of the platen, and in which the bases of the screwjacks 84 are slidable. .By this arrangement, movement of any of thescrew jacks to any position on the platen is greatly facilitated.Moreover, such of the screw jacks as are not in immediate use may remainsuspended as at 86in an out of the way position from thetplaten.

The portion of the invention thus far described pertains entirely to themechanism provided for making appropriate straightening bends in adamaged propeller blade. The mechanism for determining when a :propellerblade has been properly straightened may *be described as follows:

I Supported along opposite sidesof'the table 12 are two bars 88, aseries of adjusting screws 90 being spaced along the underside of thebars to-compensate for an sag due'tdtheweight of the bars. The two bars88 are used as ways upon which a:surface plate 92 may slide from one-endto'the other o ithe table l-'2,'the.toptsurface of the surfaceplateremaining atall times in a plane whichiis parallel .to the commonaxis of the :pilots 36. The surface pla'tez92 is :carried on mass bars94 which have guide blocks F96 secured to the outer-Lends of theibars.:In "order to simplify checking, themeasurements-from the top' of" thesurface plate to'the axis of the adapters :28 and 30 may preferably beinaeven: inches.

In the working drawing of arpropeller'bla'de, a plurality .of referencepoints on the surface of respect to their relation Since it isimpractical to measure the distance between a reference :point ionthesurface of a-blade and-.theaxis of-the pilots .36,:the distance fromthe surface plate to the "While the embodiment of the invention hereinshown is arranged for operating on two blades simultaneously, it will,of course, be understood thatone of the adapters 28 or 30 may be emittedand a machine thus. provided for operating on one blade at a time, andwhile the drawings :show the press-only in the capacity of straighteningpropellers, it is easily understood that other aircraft parts, such, forinstance, as. landing gear forks, may as readily be straightened ifsuitable adapters for holding them in proper alignment areprovided.

Having described our invention, we claim:

A press for "straightening an aircraft propeller blade which comprises:a frame structure, .a table carried by said frame structure, a, platensupported above said table by'saidframe structure,

anadapterrmounted on saidframe structurefor rotatably supporting. ablade at one and only by its shankpositioned intermediate said :tableand said platen and with axis parallel to the .plane of said table andof saidplatemwhereby a series of jacks may extend upwardly from thetable,

and a, second series: may depend from the platen,

and be arranged along the axis'of the bladeor be displaced transverselythereto, 'guideways .extending longitudinally of said table and parallelwith the axis of said adapter, guide pieces slidable along .saidguideways, and a surface'plate fast on said guide pieces, having itssurface in a plane parallel 'to theaxis of said bladeyand a gage:positioned. on said surface, said plate being movable along saidguideways into a position whereby the gage-islocated to'measure theposttionzof various parts of the bladeestablished by said jacks.

WILLIAM C. "EDWARDS, JR. ROBERT P.' ELAM.

